For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningSymptoms - Squeaks and Rattles
Table 1: Rattle Coming From the Side Rail
Table 2: Rattle Under Vehicle at Higher RPM
Table 3: Thump From Rear of Vehicle on Bumps
Table 4: Glass Knock Coming From the Rear of the Vehicle When Driving Over
Bumps
Table 5: Rattle Coming From Door
Table 6: Squeak When Operating Doors
Table 7: S ...
Installation Procedure
Install the following components on the drivetrain and front suspension
frame if removed:
The radiator support brackets.
The stabilizer shaft--Refer to Stabilizer Shaft Replacement.
The lower control arms--Refer to Lower Control Arm Replacement.
The steering gear--Refer to Steering ...
Safety System Check
Now and then, check that the safety belt reminder light, safety belts, buckles,
latch plates, retractors, and anchorages are all working properly.
Look for any other loose or damaged safety belt system parts that might keep
a safety belt system from doing its job. See your dealer to have it rep ...